Towards Layer Adaptation for Audio Transmission

2014 ◽  
Vol 6 (4) ◽  
pp. 35-41
Author(s):  
Jan Holub ◽  
Oldřich Slavata ◽  
Pavel Souček ◽  
Odysseas Zisimopoulos ◽  
Dimitris Toumpakaris ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Rate Adaptation ◽  
Physical Layer ◽  
Wireless Channel ◽  
Audio Quality ◽  
Opinion Score ◽  
Constant Rate ◽  
Channel Conditions ◽  
Channel Errors

When audio is transmitted over the wireless channel, the quality of the audio depends on the signal-to-noise ratio (SNR). The purpose of this paper is to investigate if rate adaptation can be avoided, and a system can rely instead on the audio encoder and decoder to alleviate the effect of channel errors. To this end, the paper reports on a set of experiments on various combinations of channel conditions, constellation sizes and audio encoding used and on the final audio quality achieved. The Mean Opinion Score (MOS) is used for performance evaluation. The MOS values are generated using the ITU-T P.862 (PESQ) and P.863 (POLQA) algorithms, and also using tests by experts. The results support the common practice of adapting the physical layer parameters to changing channel conditions. However, in some cases, it is possible to maintain a constant rate without impacting significantly the quality of the audio. This means that the complexity associated with physical layer and audio rate adaptation can be avoided leading to simpler and more robust designs.

scholarly journals Assessment of QoE for Video and Audio in WebRTC Applications Using Full-Reference Models

Electronics ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 462 ◽  
Author(s):  
Boni García ◽  
Francisco Gortázar ◽  
Micael Gallego ◽  
Andrew Hines
Keyword(s):  
Packet Loss ◽  
Ground Truth ◽  
Subjective Analysis ◽  
Audio Quality ◽  
Full Reference ◽  
Opinion Score ◽  
Different Types ◽  
Audiovisual Quality ◽  
Video And Audio

WebRTC is a set of standard technologies that allows exchanging video and audio in real time on the Web. As with other media-related applications, the user-perceived audiovisual quality can be estimated using Quality of Experience (QoE) measurements. This paper analyses the behavior of different objective Full-Reference (FR) models for video and audio in WebRTC applications. FR models calculate the video and audio quality by comparing some original media reference with the degraded signal. To compute these models, we have created an open-source benchmark in which different types of reference media inputs are sent browser to browser while simulating different kinds of network conditions in terms of packet loss and jitter. Our benchmark provides recording capabilities of the impairment WebRTC streams. Then, we use different existing FR metrics for video (VMAF, VIFp, SSIM, MS-SSIM, PSNR, PSNR-HVS, and PSNR-HVS-M) and audio (PESQ, ViSQOL, and POLQA) recordings together with their references. Moreover, we use the same recordings to carry out a subjective analysis in which real users rate the video and audio quality using a Mean Opinion Score (MOS). Finally, we calculate the correlations between the objective and subjective results to find the objective models that better correspond with the subjective outcome, which is considered the ground truth QoE. We find that some of the studied objective models, such as VMAF, VIFp, and POLQA, show a strong correlation with the subjective results in packet loss scenarios.

scholarly journals Evaluation of Video Quality in Wireless Multimedia Sensor Networks

2016 ◽  
Vol 6 (1) ◽  
pp. 223
Author(s):  
Mustafa Shakir ◽  
Obaid Ur Rehman ◽  
Zeeshan Abbas ◽  
Abdullah Masood ◽  
Wajeeha Shahid
Keyword(s):  
Sensor Networks ◽  
Signal To Noise Ratio ◽  
Video Quality ◽  
Discrete Event ◽  
Wireless Multimedia ◽  
Multimedia Sensor Networks ◽  
Opinion Score ◽  
Different Types ◽  
Multimedia Transmissions

<p class="Default">Simulating wireless sensor networks; there implementation and evaluation, require the use of a discrete event simulator. Omnet++ is quite a powerful simulator which supports concise and easy modeling of wired as well as wireless sensors environment. Scenarios involving multimedia transmissions with characteristics of video quality control and evaluation must be computed on the basis of Quality of Experience which relies on user’s perception to maintain the video quality. For the multimedia growth and awareness of future WMSNs, it is quite necessary that the performance should be tested for different types of radio models. So varying the radio parameters may allow for the optimization and improvement of the video quality. In this paper we have provided a test bench for the easy evaluation and optimization of the performance of WMSNs using different radio models. The performance is evaluated based on the QoE metrics; i.e. PSNR(Peak Signal-to-Noise ratio) and MoS(Mean Opinion Score), which depend on user’s perception to maintain the video quality.</p>

scholarly journals A review on link adaptation techniques for energy efficiency and QoS in IEEE802.11 WLAN

2020 ◽  
Vol 17 (1) ◽  
pp. 331
Author(s):  
Aliya Syahira Mohd Anuar ◽  
Wan Norsyafizan W Muhamad ◽  
Darmawaty Mohd Ali ◽  
Suzi Seroja Sarnin ◽  
Norfishah Ab Wahab
Keyword(s):  
Energy Efficiency ◽  
Signal To Noise Ratio ◽  
Radio Channel ◽  
Relevant Literature ◽  
Rate Adaptation ◽  
Link Adaptation ◽  
High Energy ◽  
Wireless Devices ◽  
Qos Performance

<span>Link adaptation is a technique that able to adapt modulation and coding scheme (MCS) based on radio channel conditions. With the exponential increase on the wireless devices nowadays, it contributes to high energy consumption and an increase in carbon dioxide (CO<sub>2</sub>) emission which contribute to the environmental issue. Researchers have developed proposals to tackle these issues by design algorithms based on link adaptation technique. Nowadays, various link adaptation techniques have been proposed by researchers with target for either Quality of Service (QoS) enhancement as well as energy efficiency. This paper presents A Review on Link Adaptation Techniques for Energy Efficiency and QoS in IEEE802.11 WLAN. In this study, a comprehensive review of the relevant literature published that focus on link adaptation technique in IEEE 802.11 WLAN in improving the energy efficiency and maximize the QoS performance is presented. Link adaptation can be categorized into transmission power control adaptation, transmission data rate adaptation and joint rate adaptation. These adaptations are carried out according to the channel state information (CSI). CSI can be categorized into signal-to-noise ratio (SNR), bit error rate (BER), delay, and queue length.</span>

scholarly journals Traditional protection ratios in FM sound broadcasting – still appropriate for interference management?

2011 ◽  
Vol 9 ◽  
pp. 391-396
Author(s):  
J. Philipp
Keyword(s):  
Signal To Noise Ratio ◽  
Interference Management ◽  
Audio Signal ◽  
International Telecommunication Union ◽  
Audio Quality ◽  
International Telecommunication ◽  
Broadcasting System ◽  
Proper Definition ◽  
Definition Of

Abstract. A detailed analysis of the measurement procedures recommended by the International Telecommunication Union (ITU) shows that – with proper definition of audio quality – the FM broadcasting system can provide an audio signal-to-noise ratio of no better than 40 dB, when the interference in the neighboring channels exhausts the limits established by the internationally agreed protection ratios. Thus any attempt to relax the protection, be it motivated by the desire to implement additional FM or new digital services in the FM band, would inevitably degrade reception quality of existing services to levels hardly acceptable by broadcast listeners.

scholarly journals An Adaptive Framework for Real-Time ECG Transmission in Mobile Environments

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Kyungtae Kang
Keyword(s):  
Real Time ◽  
Perceived Quality ◽  
Wireless Channel ◽  
Ecg Monitoring ◽  
Mobile Environment ◽  
Reconstructed Signal ◽  
Channel Conditions ◽  
Adaptive Framework ◽  
Ecg Data

Wireless electrocardiogram (ECG) monitoring involves the measurement of ECG signals and their timely transmission over wireless networks to remote healthcare professionals. However, fluctuations in wireless channel conditions pose quality-of-service challenges for real-time ECG monitoring services in a mobile environment. We present an adaptive framework for layered coding and transmission of ECG data that can cope with a time-varying wireless channel. The ECG is segmented into layers with differing importance with respect to the quality of the reconstructed signal. According to this observation, we have devised a simple and efficient real-time scheduling algorithm based on the earliest deadline first (EDF) policy, which decides the order of transmitting or retransmitting packets that contain ECG data at any given time for the delivery of scalable ECG data over a lossy channel. The algorithm takes into account the differing priorities of packets in each layer, which prevents the perceived quality of the reconstructed ECG signal from degrading abruptly as channel conditions worsen, while using the available bandwidth efficiently. Extensive simulations demonstrate this improvement in perceived quality.

Evaluation of Video Quality in Wireless Multimedia Sensor Networks

2016 ◽  
Vol 6 (1) ◽  
pp. 223
Author(s):  
Mustafa Shakir ◽  
Obaid Ur Rehman ◽  
Zeeshan Abbas ◽  
Abdullah Masood ◽  
Wajeeha Shahid
Keyword(s):  
Sensor Networks ◽  
Signal To Noise Ratio ◽  
Video Quality ◽  
Discrete Event ◽  
Wireless Multimedia ◽  
Multimedia Sensor Networks ◽  
Opinion Score ◽  
Different Types ◽  
Multimedia Transmissions

<p class="Default">Simulating wireless sensor networks; there implementation and evaluation, require the use of a discrete event simulator. Omnet++ is quite a powerful simulator which supports concise and easy modeling of wired as well as wireless sensors environment. Scenarios involving multimedia transmissions with characteristics of video quality control and evaluation must be computed on the basis of Quality of Experience which relies on user’s perception to maintain the video quality. For the multimedia growth and awareness of future WMSNs, it is quite necessary that the performance should be tested for different types of radio models. So varying the radio parameters may allow for the optimization and improvement of the video quality. In this paper we have provided a test bench for the easy evaluation and optimization of the performance of WMSNs using different radio models. The performance is evaluated based on the QoE metrics; i.e. PSNR(Peak Signal-to-Noise ratio) and MoS(Mean Opinion Score), which depend on user’s perception to maintain the video quality.</p>

scholarly journals Experimental Study on the Performance of Rate Adaptation Algorithm in IEEE 802.11g Networks

2021 ◽  
Author(s):  
◽  
Dong Xia
Keyword(s):  
Ieee 802.11 ◽  
Real World ◽  
Rate Adaptation ◽  
Data Rate ◽  
Wireless Channel ◽  
Adaptation Algorithm ◽  
Fixed Rate ◽  
Channel Condition ◽  
Channel Conditions ◽  
World Environment

<p>IEEE 802.11 technology provides a low-cost wireless networking solution. In the last few years, we have seen that the demand for high-bandwidth wireless local area networks increases rapidly, due to the proliferation of mobile devices such as laptops, smart phones and tablet PCs. This has driven the widespread deployment of IEEE 802.11 wireless networks to provide Internet access. However, wireless networks present their own unique problems. Wireless channel is extremely variable and can be affected by a number of different factors, such as collisions, multipath fading and signal attenuation. As such, rate adaptation algorithm is a key component of IEEE 802.11 standard which is used to vary the transmission data rate to match the wireless channel conditions, in order to achieve the best possible performance. Rate adaptation algorithm studies and evaluations are always hot research topics. However, despite its popularity, little work has been done on evaluating the performance of rate adaptation algorithms by comparing the throughput of the algorithm with the throughput of the fixed rates. This thesis presents an experimental study that compares the performance ofMikroTik rate adaptation algorithm andMinstrel rate adaptation algorithm against fixed rates in an IEEE 802.11g network. MikroTik and Minstrel rate adaptation algorithm are most commonly used algorithm around the world. All experiments are conducted in a real world environment in this thesis. In a real world environment, wireless channel conditions are not tightly being controlled, and it is extremely vulnerable to interference of surrounding environment. The dynamic changes of wireless channel conditions have a considerable effect on the performance of rate adaptation algorithms. The main challenge of evaluating a rate adaptation algorithm in a real world environment is getting different experiment behaviours from the same experiment. Experiment results may indicate many different behaviours which due to the leak of wireless environment controlling. Having a final conclusion from those experiment results can be a challenge task. In order to perform a comprehensive rate adaptation algorithm evaluation. All experiments run 20 times for 60 seconds. The average result and stand deviation is calculated. We also design and implement an automation experiment controlling program to help us maintain that each run of experiment is following exactly the same procedures. In MikroTik rate adaptation algorithm evaluation, the results show in many cases that fixed rate outperforms rate adaptation. Our findings raise questions regarding the suitability of the adopted rate adaptation algorithm in typical indoor environments. Furthermore, our study indicates that it is not wise to simply ignore fixed rate. A fine selection of a fixed rate could be made to achieve desired performance. The result ofMinstrel rate adaptation evaluation show that whilst Minstrel performs reasonably well in static wireless channel conditions, in some cases the algorithm has difficulty selecting the optimal data rate in the presence of dynamic channel conditions. In addition, Minstrel performs well when the channel condition improves frombad quality to good quality. However, Minstrel has trouble selecting the optimal rate when the channel condition deteriorates from good quality to bad quality. By comparing the experimental results between the performance of rate adaptation algorithms and the performance of fixed data rate against different factors, the experiment results directly pointed out the weakness of these two rate adaptation algorithms. Our findings from both experiments provide useful information on the design of rate adaptation algorithms.</p>

scholarly journals Experimental Study on the Performance of Rate Adaptation Algorithm in IEEE 802.11g Networks

2021 ◽  
Author(s):  
◽  
Dong Xia
Keyword(s):  
Ieee 802.11 ◽  
Real World ◽  
Rate Adaptation ◽  
Data Rate ◽  
Wireless Channel ◽  
Adaptation Algorithm ◽  
Fixed Rate ◽  
Channel Condition ◽  
Channel Conditions ◽  
World Environment

<p>IEEE 802.11 technology provides a low-cost wireless networking solution. In the last few years, we have seen that the demand for high-bandwidth wireless local area networks increases rapidly, due to the proliferation of mobile devices such as laptops, smart phones and tablet PCs. This has driven the widespread deployment of IEEE 802.11 wireless networks to provide Internet access. However, wireless networks present their own unique problems. Wireless channel is extremely variable and can be affected by a number of different factors, such as collisions, multipath fading and signal attenuation. As such, rate adaptation algorithm is a key component of IEEE 802.11 standard which is used to vary the transmission data rate to match the wireless channel conditions, in order to achieve the best possible performance. Rate adaptation algorithm studies and evaluations are always hot research topics. However, despite its popularity, little work has been done on evaluating the performance of rate adaptation algorithms by comparing the throughput of the algorithm with the throughput of the fixed rates. This thesis presents an experimental study that compares the performance ofMikroTik rate adaptation algorithm andMinstrel rate adaptation algorithm against fixed rates in an IEEE 802.11g network. MikroTik and Minstrel rate adaptation algorithm are most commonly used algorithm around the world. All experiments are conducted in a real world environment in this thesis. In a real world environment, wireless channel conditions are not tightly being controlled, and it is extremely vulnerable to interference of surrounding environment. The dynamic changes of wireless channel conditions have a considerable effect on the performance of rate adaptation algorithms. The main challenge of evaluating a rate adaptation algorithm in a real world environment is getting different experiment behaviours from the same experiment. Experiment results may indicate many different behaviours which due to the leak of wireless environment controlling. Having a final conclusion from those experiment results can be a challenge task. In order to perform a comprehensive rate adaptation algorithm evaluation. All experiments run 20 times for 60 seconds. The average result and stand deviation is calculated. We also design and implement an automation experiment controlling program to help us maintain that each run of experiment is following exactly the same procedures. In MikroTik rate adaptation algorithm evaluation, the results show in many cases that fixed rate outperforms rate adaptation. Our findings raise questions regarding the suitability of the adopted rate adaptation algorithm in typical indoor environments. Furthermore, our study indicates that it is not wise to simply ignore fixed rate. A fine selection of a fixed rate could be made to achieve desired performance. The result ofMinstrel rate adaptation evaluation show that whilst Minstrel performs reasonably well in static wireless channel conditions, in some cases the algorithm has difficulty selecting the optimal data rate in the presence of dynamic channel conditions. In addition, Minstrel performs well when the channel condition improves frombad quality to good quality. However, Minstrel has trouble selecting the optimal rate when the channel condition deteriorates from good quality to bad quality. By comparing the experimental results between the performance of rate adaptation algorithms and the performance of fixed data rate against different factors, the experiment results directly pointed out the weakness of these two rate adaptation algorithms. Our findings from both experiments provide useful information on the design of rate adaptation algorithms.</p>

Pre-Processing of Hyperspectral Images Using Nonlinear Filters

2013 ◽  
Vol 11 (1) ◽  
pp. 8-13
Author(s):  
V. Behar ◽  
V. Bogdanova
Keyword(s):  
Signal To Noise Ratio ◽  
Correlation Coefficients ◽  
Hyperspectral Images ◽  
Spectral Correlation ◽  
Edge Preserving ◽  
Improvement Factor ◽  
Filter Output ◽  
Average Improvement ◽  
Processing Procedure

Abstract In this paper the use of a set of nonlinear edge-preserving filters is proposed as a pre-processing stage with the purpose to improve the quality of hyperspectral images before object detection. The capability of each nonlinear filter to improve images, corrupted by spatially and spectrally correlated Gaussian noise, is evaluated in terms of the average Improvement factor in the Peak Signal to Noise Ratio (IPSNR), estimated at the filter output. The simulation results demonstrate that this pre-processing procedure is efficient only in case the spatial and spectral correlation coefficients of noise do not exceed the value of 0.6

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